Practice exam 1 Chem

J.J Thomson is credited with discovering the electron: T/F
True False

Two isotopes of the same element can have a different number of protons:T/F
True False

Two isotopes of the same element can have a different number of electrons: T/F
True False

The symbol for magnesium is Mn : T/F
True False

As5+ has 33 protons and 28 electrons : T/F
True False

The answer to the following mathematical operation (18.5-11.4) has three significant figures: T/F
True False

A homogeneous mixture can be made by completely dissolving salt into water : T/F
True False

It is impossible to round 45,629.54 to three significant figures : T/F
True False

The density of a pure compound changes depending on how much liquid is present: T/F
True False

A mass of 456.2 g of brass (72% copper, 28% zinc) contains 328.5 g zinc: T/F
True False

An increase of 1°F corresponds to an increase of 1.8°C : T/F
True False

A hypothesis will predict the outcome of all future experiments : T/F
True False

Perform the following calculations and indicate the results to the correct number of significant figures:
1.24 x 3.796 =

Perform the following calculations and indicate the results to the correct number of significant figures. 
4.17 + 13.1 + 6.14 =

Perform the following calculations and indicate the results to the correct number of significant figures. 
(14.35 – 7.12) x (12.3 + 3.58) =

convert to standard:
1.403 x 103

covert to standard:
2.85 x 10-4

covert to standard:
1.67 x 10-2

convert to scientific notation:
1.259 x 103

convert to scientific notation:
4.6 x 10-3

convert to scientific notation:
2.10006 x 101

523 nm to m

219 K to°F

66 mi/hr to km/s

1 year to seconds (Scientific Notation)

Magnesium has three naturally occurring isotopes 24Mg (78.99%), 25Mg (10.00%), and 26Mg (11.01%).  What is the isotopic mass of 25Mg if the mass of 24Mg is 23.985 amu and the mass of 26Mg is 25.983 amu?